If so, where might I find one and what would I use it for?
Rimfire rifles strike the rim of the casing to ignite the primer rather than the center of the cartride. For this to work the cartridge walls need to be thin enough to be crushed by the firing pin and ignite the primer. These thin brass walls limit the amount of gunpowder that may be used and consequently their use is limited to small calibers. The 22LR (Long Rifle) is the most common round using a rimfire setup.
Rimfire rifles may not be used big game hunting in Idaho. More information about rimfire ammunition may be found on wikipedia.